. >> bernard l. madoff securities employed over 100 people, but it seemed like a family business. his brother peter and several cousins worked there. mark and andrew worked on the 19th floor of new york's lipstick building, where they legitimately traded securities for the firm and for outside clients. the investment advisory business--the ponzi scheme-- was housed two floors below, where their father never made any trades at all. he was simply creating phony paper statements that showed steady profits for his clients, his victims. access to the 17th floor was highly restricted. you must have been curious about why the 17th floor was such a secret place. when you or mark asked him about his end of the business, what did he say? >> it was always very similar responses. "you guys have your business to worry about, and let me worry about my business," and the conversation would end there. >> but people say, "look, there's no way these kids could not have at the very least suspected something was going on." >> well, keep in mind these were completely separate businesses. we were execu